Antioxidant Potential And Neuroactive Properties Of Malus Domestica: An In-Vitro DPPH Assay And GABA Modulation Clinical Study

Background: Malus domestica (apple) is widely recognized for its rich phytochemical composition and associated health benefits, yet its combined antioxidant potential and neuroactive effects remain underexplored. Objective: This study evaluated the in vitro antioxidant activity of Malus domestica extracts and assessed their potential neuroactive effects through modulation of plasma γ-aminobutyric acid (GABA) levels in a clinical pilot study.Methods: Methanolic extracts of apple powder were analyzed for phytochemical content and tested using the DPPH radical scavenging assay at concentrations ranging from 50–400 µg/mL. For the clinical component, 40 healthy adults participated in an 8-week randomized, placebo-controlled trial; plasma GABA levels were measured pre- and post-intervention using ELISA. Statistical analyses included descriptive statistics, normality testing, paired comparisons, and correlation analysis. Results: The apple extract demonstrated strong dose-dependent antioxidant activity, with mean % inhibition of approximately 58.9% and IC₅₀ consistent with reported values for polyphenol-rich extracts. Clinically, participants receiving the apple extract showed a modest increase in mean plasma GABA levels (from 6.50 ng/mL to 7.15 ng/mL). Correlation analysis revealed a moderate positive relationship between baseline and post-intervention GABA levels (r = 0.565, p = 0.035), though changes in GABA were not significantly correlated with IC₅₀ values (r = 0.220, p = 0.449). Conclusion: Malus domestica exhibits notable in vitro antioxidant activity and potential to modestly enhance plasma GABA levels, suggesting neuroactive properties. Further large-scale studies are warranted to confirm these findings and elucidate underlying mechanisms.